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NIAGARA FALLS: 



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PHYSICAL CHANGES, 



THE GEOLOGY AND TOPOGRAPHY 



THE SURROUNDING COUNTRY. 

1- 



BY JAMES HALL, 
M 

State Geologist of New York ; Corresponding Member Bust. Soc. Nat. Hist., &c. 



[From the Boston Journal of Natural History.] 



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NIAGARA FALLS. 



The cataract of Niagara and the geology of the surround- 
ing country, have been often described ; but beheving that 
there are many facts unnoticed, and others which have not 
had due weight in these considerations, I shall venture a fur- 
ther attempt at illustrating some important points regarding 
this great finger post in the path of time. I am far from 
asserting that the problem regarding the recession or the for- 
mer condition of this great cascade is settled. So many dis- 
turbing causes are constantly jiresenting themselves, that al- 
though the great principles may be deemed established, yet it 
is impossible to calculate accurately the effect of these minor 
influences. Every fact recorded of the past, the present, or 
the future condition of this cataract will aid in the calculation 
of the final result, which, some thousands of years hence, 
may be made with tolerable accuracy. In the mean time we 
must content ourselves with observing these facts and laying 
down land-marks for the guidance of those who may follow 
us in the attempt to decide the eflect of time upon these an- 
cient rocks. 

A striking feature in the Topography of western New York, 
is the great diffei-ence of elevation between the Lakes Erie 
and Ontario, when taken in connexion with the generally 
level or but slightly uneven surface of the country, and where 
there are no disturbances among the strata. The difference 
of elevation between the other great lakes is comparatively 
small, although Superior is situated in a disturbed geological 
region. The elevation of Lake Erie is three himdred and 
thirtyfour feet above Lake Ontario, and the greater part of the 
difference is overcome by Niagara river in the sjjace of one 
mile at the rapids and falls. 

The barrier at the outlet of Lake Erie is formed by a ter- 
race of limestone which extends from the Hudson river, west- 



4 HalVs Remarks on Niagara Falls 

ward far into Canada, forming for many miles the northern 
boundary of the lake. The southern slope of this terrace or 
platform of limestone passes off beneath the water, forming 
the bed of the lake. This terrace terminates abruptly on the 
north, within a short distance of the lake, and we descend 
into a low, level country, underlaid by marks and shales of 
the saliferous formation, which extend for a distance of fifteen 
or eighteen miles. Beyond this, there is an almost impercep- 
tible ascent for eight miles, when it suddenly plunges down 
about 250 feet, over the outcropping edges of various strata, 
which here terminate abruptly, to the low table land, border- 
ing Lake Ontario. From the base of this escarpment, the 
country slopes almost imperceptibly to the level of the lake, 
seven miles distant, and one hundred and twenty feet lower. 
A great portion of the country for twenty miles north of the 
first terrace, or that bordering Lake Erie, is so level that a 
rise of the Niagara river for thirty feet, would inundate an 
extent of thirty miles on both sides. After leaving the level 
country, the ascent, as before stated, is very gradual to the 
north ; but when we arrive at the edge of the great terrace of 
Lewiston and Q,ueenston, the elevation is thirtyeight feet 
above the level of Lake Erie. The general outline of this 
part of the country will be seen in the section from Erie to 
Ontario. 

This great terrace or platform is known in New York as 
the mountain ridge, and in Canada as Q,ueenston heights. It 
extends to the westward of Niagara river, beyond the head of 
Lake Ontario, and eastward beyond the Genesee river, where 
it merges in the general level of the country ; partially from 
the dip of the rocks in that direction, and partially from the 
thinning of some of its members. The abrupt termination 
of the various strata in the face of this cliff, prove conclusively 
the extent of denuding action upon this portion of the coun- 
try. The basin of Ontario, on the north of the terrace, has 
evidently been excavated from the sedimentary strata, the 
limit of deiuiding agency and that of the lake basin being 
the line of this escarpment. The edge of this escarpment is 
indented by numerous ravines or gorges, extending to a great- 



and the Geology of the Surrounding Country. 5 

er or less distance ; they usually present a broad opening to 
the north, and terminate at a point within the first mile, and 
generally within a shorter distance. The streams now flow- 
ing in these ravines, evidently had little or nothing to do 
with their excavation, as the space is partially filled with 
drift, a deposit from another source. These indentations are 
doubtless in part the etfects of the great denuding agency 
which produced the escarpment, by undermining and remov- 
ing the different materials. 

It has been supposed by some, and Dr. Daubeny has 
adopted the opinion, that the terrace or escarpment at Lewis- 
ton was produced by a fault ; either an uplifting of all the 
strata on the sonth, or a downthrow of those on the north. 
Not having Prof. Daubeny's paper before me, I cannot state 
his arguments, but whatever they may be, they are certainly 
unsupported by facts. The strata are all visible in either di- 
rection, and there is no evidence of even the smallest disturb- 
ance. 

The strata, as they are exposed in the terrace of Lewiston 
and Q,ueenston, and in the banks of the river on either side, 
are exhibited in the section on the next page. 

There is here not only no evidence of a fault causing the 
difference in elevation, but direct proof to the contrary ; the 
soft marl and shale, forming the base of the cliff in the river 
banks, underlies the plateau from this place to Lake Ontario, 
and is visible, almost continuously, for the whole distance. 
On the other hand, there are the most unequivocal proofs of 
denuding action, and that the whole basin of Ontario is due 
to the excavating power. It will be seen that the character 
of the strata is such as to ofter great facilities for the operation 
of such an agent, consisting of alternating hard and soft beds. 
The action of water would undermine the harder, and leave 
them to fall by, their own weight, while the softer materials 
were removed. The denudation of such extensive districts, 
could only have taken p.lace while the country was submer- 
ged, and during the period of its elevation from beneath the 
ocean. This principle has been recognized by Mr. Hayes, in 
his description of the " Geology and Topography of Western 



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HalVs Remarks on Niagara Falls. 7 

New York,"* By adopting this mode of explanation, we are 
enabled to account for the existence of this and similar terra- 
ces, along the lines of bearing of our extensive limestone 
formations, as well as for the deep valleys of ancient origin. 

The strata forming the escarpment at Lewiston, as seen in 
the section, are those through which the chasm of the Niaga- 
ra is excavated. The whole dip gradually to the south, and 
all below No. 8, disappear below the level of the river before 
reaching the falls, as may be seen by the dotted line bed which 
represents the surface of the river below the falls. The strata 
above this line are those excavated to form the channel of the 
river. The limestone forming the summit of the terrace, and 
at its margin not more than twenty feet thick, gradually in- 
creases from the addition of higher layers, till at the falls it 
has acquired a thickness of one hundred and twenty feet. 
This limestone, about one mile south of the falls, disappears be- 
neath the surface, and is succeeded by a soft marl of a bluish 
or greenish grey color, with purple bands. This formation, 
which is a continuation of the Onondaga saliferous group, 
occupies all the level country from two miles south of the 
falls, to Black Rock, a distance of eighteen miles by the 
course of the river. This is succeeded by the water limestone 
and Helderberg limestone group. The saliferous formation, 
occupying this great breadth of country, and forming an im- 
portant item in any calculation regarding the recession of the 
falls, has nevertheless always been overlooked by observers, 
and its existence in that part of the country was never noticed 
by any one, till the publication of the New York Geological 
Reports, in 1838. Previously, all the distance between the 
falls and Lake Erie was considered as underlaid by limestone ; 
and the limestone of Black Rock, or the Helderberg group, 
was placed immediately above the Niagara limestone, and 
represented as resting upon it. 

The Niagara river, in its escape from Lake Erie, has exca- 
vated a passage through the Helderberg limestone, (No. 10,) 
which forms the upper terrace before noticed, leaving a small 

• Am. Journal of Science, Vol. XXXV. No. I. 



6 Hairs Remarks on Niagara Falls 

island, known as Bird's Island, in the midst of the stream. 
From Black Rock to within two miles of the great fall, the 
cliannel is excavated in the rocks of the saliferous group, the 
descent in this distance being only fifteen feet. About one 
mile south of the fall, the Niagara limestone approaches the 
surface, and forms the commencement of the rapids. The 
current, for the first two miles after leaving the lake, is 
very rapid ; after this distance, it flows on more gently, the 
channel gradually widening as far as Grand Island, where it 
is nearly two miles wide. It then divides, the greater quan- 
tity of water running on the west side of this island. There 
are several small, low islands in the river, above Grand Island, 
but this is far larger than all of them. Below this island the 
river expands to a width of two or three miles, and presents 
all the appearance of a quiet lake with small, low islands. 
Approaching the rapids, the river narrows, and the current 
becomes more rapid, and for about one mile before reaching 
the grand cascade, rushes on with inconceivable velocity, 
over a declivity of fifty two feet, to the edge of the precipice, 
where it is precipitated into a gulf one hundred and sixty feet 
below. 

The chasm through which the Niagara river flows, from 
this point to its emergence into the low country at Lewiston, 
is excavated in the rocks represented in the section, Nos. 7 
and 8 only being visible at the falls, the others rising succes- 
sively from beneath the water, owing to the declivity of the 
bed of the river, and the ascent of the rocks to the northward. 
The sides of this chasm present almost perpendicular walls, 
with a talus at the bottom, formed by the falling of some of 
the higher masses. The outlet of this chasm, where the 
river emerges into the plain at Lewiston, is scarcely wider 
than elsewhere along its course. In some places the river 
flows in a channel of less than two hundred yards across, and 
again is expanded to twice that width. The breadth of the 
chasm across the top, is nearly twice that of the channel or 
stream at the bottom. The declivity of the bed of the river, 
from the falls to Lewiston, is one hundred and four feet, or 
nearly fifteen feet to the mile, which gives great velocity to the 



and the Geology of the Surrounding Country. 9 

stream. At one place, however, about a mile below the fall, 
and where the channel is narrowest, the stream glides along 
with comparative quiet, while below this, where the channel is 
broader, it is thrown into great confusion. Again, below the 
whirlpool the surface of the river is more smooth, and the 
current more gentle, though the channel is narrower than 
above. The cause of these appearances, which have seemed 
inexplicable upon the common theory, and have been used as 
arguments against the recession of the falls, is to be sought in 
the geological structure of the place. It will be seen that 
below the whirlpool there are no hard rocks in the bed of the 
river, and consequently the channel is deeper than where such 
rocks exist. At the whirlpool, and above that place, the hard 
sandstone. No. 2, is at and near the level of the river, and 
consequently the channel is not worn so deep. Again, after 
this hard mass has dipped beneath the surface, the channel is 
excavated in softer rocks ; hence the narrow channel and 
smooth water a mile below the falls. Near the falls, the 
higher beds of sandstone and the Protean limestone come to 
the level of the river, and thus cause a wider, shallow channel, 
and more tumultuous water. Such, simply, I conceive to be 
the explanation of the variable width of the chasm, and the 
greater or less violence of the water. 

Upon the west bank of the river, at the whirlpool, there is 
a depression, and a deflection in the course of the river to the 
right, as will be seen by referring to the map. Standing 
upon the east bank of the river, this depression has the ap- 
pearance of having been worn by the eddying current of the 
stream ; but on farther investigation it proves to be of differ- 
ent origin. During a recent visit, in company with Mr. Lyell, 
Ave examined this place, and found it to be an ancient gorge, 
filled with drift, except a narrow ravine through which a 
small stream flows into the river. This stream may be traced 
in a north-west direction for two miles, where it comes to the 
level of the surrounding country. In one or two places, near 
the river, the bed of this stream has laid bare the rocks, 
which proves that they are not excavated so deeply as the bed 
of the Niagara. From the termination of this ravine, upon 
2 



10 HalVs Remarks on Niagara Palls 

the table land, going in a north-west direction about one mile, 
we commence descending through another deep gorge, which 
terminates upon the plateau at the base of the escarpment, at 
St. Davids. It will be perceived, by referring to the map, that 
the course of the river before coming to the whirlpool, if con- 
tinued in the same direction, would lead to St. Davids. From 
this fact it has been inferred that there is a continuous ancient 
ravine, filled with drift, from the whirlpool to this place. 
This most remarkable fact has been cited as a strong objection 
to the theory of recession by the action of the river upon its 
own bed. Still, however, I hope to show that its existence 
is equally an objection to the chasm having been produced by 
the action of the sea. 

If this ravine be continuous from the whirlpool to St. Da- 
vids, and existed previous to the excavation of the Niagara 
channel to Lewiston, it seems natural to suppose that it 
would have taken that direction. If we suppose that the 
undermining agency of the ocean, aided by the stream, exca- 
vated the Niagara chasm, why would not the same agency 
have cleared out this ancient ravine ? And if it be assumed 
that the stream had commenced flowing by way of Lewiston, 
then we require nothing more to account for the commence- 
ment of the chasm. The assumption that the sea excavated 
the present channel of Niagara, does not aid in the difficulty 
of explaining why the ancient ravine of St. Davids was not 
cleared out ; but on the other hand, the existence of that 
ravine, filled with drift, is a strong argument that the Niagara 
did excavate, of itself chiefly, its present channel. For had 
the sea remained long enough after the filling of this ravine 
with drift, to excavate that of Niagara, it would have removed 
a portion at least of it, and have drained the water in that di- 
rection. We can scarcely conceive it possible that this ravine 
could have been filled with drift, by any means, while such a 
stream as the present Niagara river was flowing through it, 
and if it has, at any time, been a large water course, there 
must have been a cessation of the stream during the time of 
this filling up. 

The most rational explanation, ar.d the one most consonant 



and the Geology of the Surrounding Country. 1 1 

with existing facts, appears to me to be, that the ravine of St. 
Davids was excavated by the power of the waves, aided prob- 
ably by a stream, though it may have been a very insignificant 
one\ That this ravine was formed previously to the period of 
the drift, and that during this time it became filled with the 
transported materials to such an extent that the stream after- 
wards was unable to excavate a channel through the mass. 
Under these circumstances, the water would find an outlet at 
the lowest point, into the basin of Ontario ; whether that 
point were over a surface of rock or of drift, and after the 
channel was once commenced, it would go on deepening, un- 
less some violent change should alter the configuration of the 
surface. Now there is no evidence of such a change in the 
Niagara district, and it seems more rational to conclude that 
the stream, which may have formerly found its way through 
the ravine of St. Davids, after the filling up of that channel, 
took the course by Lewiston, that being the lowest point at 
which it could find a passage to the lower country on the 
north. It may be necessary, perhaps, to suppose a depression 
in this direction before the water would flow there ; and such 
a depression may have existed from causes in operation previ- 
ously, or there may have been an indentation in the edge of 
the terrace at this place, like those farther east, near Lockport. 
There appears, indeed, strong reason for supposing that there 
was a depression in the surface at the place where the river 
now flows, before the deep channel was excavated ; there is a 
general depression on either side, and a transverse section of 
the river would present the appearance represented in the an- 
nexed diagram. 



The recent deposit, forming Goat Island, is upon a surface 
lower than the top of the rapids, indicating removal of the 



12 HalVs Remarks on Niagara Falls 

surface rock to some extent, before the period of that form- 
ation. 

I will now proceed to consider, first the objections to the 
theory that this ravine was produced by the combined action 
of the stream and the waves of the sea ; and next the argu- 
ments in favor of the hypothesis that the river has excavated 
its own channel, or by far the greater portion of it. 

Examples are not unfrequent where the closing up of an 
outlet by drift, has caused the excavation of a new channel 
through solid rock. Perhaps the best illustration of this fact 
occurs in the passage of the Genesee river from the upper to 
the lower valley, from Portage to Mount Morris. The river, 
flowing from the south as far as Portage, is suddenly turned 
around to the opposite direction, and then again turns to the 
north, cutting its channel for about two miles through solid 
rock, in some parts to the depth of three hundred and fifty 
feet. At the end of this chasm it emerges into a more an- 
cient valley, and at a point which would communicate with 
the river at Portage, before its deflection, by less than half the 
distance which it has required in its present course to reach 
this place. Now had this short space been occupied by a 
bluff" of rock, we should easily have found an explanation of 
the reasons why the river did not pursue a direct course. But 
what are the facts ? This shorter space, intervening between 
the two portions of the channel, is occupied by a deep deposit 
of drift, rising higher than the surface of the rocks where the 
river has found its channel. In the process of examination 
and excavation for the Genesee valley canal it has been found 
that this drift is of great depth, extending even beloAV the 
level of the present bed of the river. The question presents 
itself, why did not the stream remove the gravel and sand, 
and make itself a channel in the shortest direction, instead of 
going twice as far through rocky strata ? Or if we advance 
the argument that this chaimel was excavated in part by the 
aid of the sea, why did not this undermining agency aff'ect 
this deposit of sand and gravel ? The truth is incontroverti- 
ble that many streams have excavated their channels to great 
depths in rocky strata, long after the ocean left the surface. 



and the Geology of the Surrounding Country. 13 

Passing lower down on the Genesee river, there are other 
places where the stream has left the old channel, now filled 
with drift, and formed a new one, through rocky strata ; and 
finally, at Mount Morris, it emerges into another ancient val- 
ley from a narrow gorge bounded by mural escarpments. It 
would be absurd to assert, that broad valleys, with sloping 
sides, filled, or partially filled with drift, are of the same age, or 
due to the same agency, as the narrow, deep valleys or chasms 
with clean, rocky embankments, and containing no other loose 
materials than those arising from the adjacent rocks. 

Similar examples may be found in the outlets of Seneca 
and Cayuga Lakes, which flow into Lake Ontario. Now the 
course of these outlets is not in a direct line north to the 
lake, but from Seneca it turns to the eastward, excavating its 
course through the limestone and gypsum beds, between that 
lake and Cayuga. From all examinations I have made, there 
appears to be an ancient valley, filled with drift, between the 
northern end of Seneca Lake and Ontario ; and yet, notwith- 
standing this, the stream has excavated harder materials, and 
taken a much more circuitous route to Lake Ontario. The 
same explanation may be given of Canandaigua and the outlets 
of other lakes. 

As an analogous case, we may compare the ravine of St. 
Davids and the whirlpool, with that of Iroijdequoit, a few 
miles east of Rochester. The Genesee river, after leaving 
the gorge at Mount Morris, flows in the bottom of an ancient 
valley to within a short distance of Rochester, where it enters 
a new channel. This channel is narrow, with almost perfect 
mural banks, and nowhere contains deposits of drift. On the 
lake shore, about two miles east of the mouth of the Genesee, 
we find a broad and deep ravine, known as the Iroudequoit 
bay. This ravine is excavated to an unknown depth below 
the level of Lake Ontario. The Iroudequoit creek which 
takes its rise in the southern part of the county, flows through 
this ravine for a few miles before reaching the lake. This 
ravine presents a very diflerent appearance from either that of 
the Genesee below Rochester, or of the Niagara, and no one 
could suppose that the present stream had ever excavated such 



14 HalVs Remarks on Niagara Falls 

a channel. At tlie lake shore, it has a broad opening with 
sloping sides, and appears much like a bay worn by the action 
of the sea, while perhaps a stream was flowing in at the same 
place. It appears very natural to suppose that this may at 
one time have been the continuation of the ancient valley of 
the Genesee, which was commenced south of Dansville, and 
continued northward as the land was upraised above the sea. 
Now had the sea ever washed the base of the cliffs at Lew- 
iston long enough to allow of the excavation of this gorge of 
the Niagara, we should find some evidence of its sojourn there, 
in the shape of a beach, or rounded pebbles ; but we find 
nothing of the kind. The continuance of a line of coast of 
sea or lake may be determined comparatively by the charac- 
ter of the materials along its margin ; whether they are com- 
pletely rounded, or still much angular ; or if rounded, whether 
the forms are very much flattened. But in the case before us 
we find nothing at a greater elevation than the ridge road, or 
lake ridge, which, from its nature and contained remains, must 
have been the boundary of an ancient lake. 

Other examples might be cited, but these appear to me suf- 
ficient as an explanation of causes why the Niagara did not 
take its course from the whirlpool through the ravine filled 
with gravel, rather than excavate a new channel from the 
rock. 

We come now to the consideration of the argument that 
the chasm of Niagara has been worn by the sea, previous to, 
or during the elevation of this part of the country above its 
level. In the absence of direct proof, we must resort to anal- 
ogy, and relying on this mode, we find that all indentations 
or ravines, excavated in the face of sea cliffs, have a broad or 
trumpet-mouthed opening toward the sea, and recede abruptly 
to a point. They never present a long, narrow ravine, of 
equal width ; and when of a length at all approaching Ni- 
agara, they have an opening many times broader than this at 
Lewiston. I might cite numerous examples of ravines exca- 
vated by the sea, aided by a stream coming in at right angles, 
but none of these are of the character of Niagara. In such 
cases they are broad enough to allow the stream to flow 



and the Geology of the Surrounding Country. 15 

through the bed, leaving waterworn materials along the sides, 
monuments of the wearing action of the waves. In the 
Niagara chasm there are no pebbles, boulders, or gravel ; the 
river occupies nearly the whole width at the bottom, allowing 
a talus of angular fragments of the rocks fallen from above. 

The valley of the Genesee, from Rochester to Dansville, 
affords a good example of a ravine excavated during the 
emergence of land from beneath the sea ; but this valley is 
broad, and partially filled with drift, the sides sloping gradu- 
ally and for the most part covered with deep soil, partially 
from decomposition and disintegration of the rocks beneath, 
but principally from trans])orted materials. 

The small amount of wearing accomplished by a stream 
during the period of our observation might incline us to 
doubt the possibility of any body of water having excavated 
its channel backwards for a length of seven miles, and to a 
depth of from three to five hundred feet. But if the period 
of one life be sufficient to admit of observation proving the 
smallest amount of recession, then it is only requisite that we 
should carry on the process for an indefinite period, to accom- 
plish the utmost that we require ; or, that we extend back- 
ward our imagination regarding time, in order to prove what 
is already accomplished. Now it is attested, within the re- 
corded observations of those residing in the vicinity of Niaga- 
ra, that the falls have receded within their recollection. If 
then it is proved that this ravine could not have been excava- 
ted by the sea during the emergence of the land, we have 
<mly this mode of operation left to account for its formation. 

From analogous facts, we learn that it only requires an ele- 
vation of the drift, filling up the old channel, to be greater 
than that of the rocky strata, in order to turn the water in 
that direction, and cause it to form a new channel. We 
have only to suppose the ravine, from the whirlpool to St. 
Davids, filled, as it now is, with drift, to such a height as to 
prevent the water from flowing in that direction, and the con- 
sequence would be, as I said before, that it would seek an 
outlet at the lowest point along the terrace, which appears to 
have been in the direction of Lewiston. Here the water 



16 HalVs Remarks on Niagara Falls 

commenced the work of excavation, cutting down the higher 
strata, and rapidly undermining and removing those below. 
It is only necessary to refer to the accompanying section, in 
order to discover what materials the river had to work upon 
at this period. 

It is impossible that there could ever have been a perpen- 
dicular fall of the whole height of the cliff at Lewiston, for 
the limestone at the top, being so much thinner than at the 
present falls, would soon be broken down by the pressure of 
the immense body of water precipitated over its edge upon 
the shale below. It may even be doubted whether the shale 
would be excavated fast enough to form a perpendicular fall, 
and it is probable that the water would be projected over a 
declivity of the upper shale (No. 7,) to the limestone below, 
which together with the higher layers of the sandstone would 
form the crest of a second fall. From this again the water 
would be precipitated as far as the sandstone, (No. 2,) where 
a third fall would be formed. Thus, instead of a single fall 
of three hundred and fifty feet, we should have the whole 
height divided into three falls, at some distance from each 
other. In consequence of the thinness of the upper limestone, 
that fall would recede faster than either of those below it ; 
and the middle faster than the lower one. Even under these 
circumstances, the wearing action would go on much faster 
than at present. Finally, however, the recession would be- 
come less and less rapid, from the thickening of the limestone 
above ; and from this cause, the two lower falls having the 
same resistance to overcome as at first, would gradually ap- 
proach the upper, till the whole became one. 

At the same time there are other circumstances to be taken 
into consideration, and among the most important of these 
will be the dip of the strata and the ascent of the bed of the 
stream ; both together tending to bring the strata down to 
the level of the water as we progress southward. This fact 
has also an important bearing upon the rate of recession ; for 
while a hard mass remains at a considerable height above 
water, with a soft one below, the excavation of the softer one 
and underminiiig of the upper hard one, tends to the recession 



and the Geology of the Surrounding Country. 17 

much more rapidly than if the whole were of uniform char- 
acter. Thus it must have been that the fall over the sand- 
stone, (No. 2,) receded much more rapidly while there was a 
considerable thickness of shale below, than when it approach- 
ed the level of the water. This would happen after the falls 
had retreated about three miles, or nearly to the whirlpool. 
At this point the recession would go on very slowly for a long 
period, for this hard mass, being at the level of the water, 
would effectually suspend the undermining process. Even at 
the present time the mass may be seen stretching into the 
river from either side beyond the other rocks, and at the point 
where it crosses, producing a fall of eight or ten feet within 
a few rods. 

After this long and almost stationary period at the whirl- 
pool, the recession would again go on more rapidly ; soft ma- 
terials being presented at the river level to be excavated by 
the force of the falling water, which would thus undermine 
the harder mass above. 

When the cascade had receded to near its present position, 
another pause similar to that at the whirlpool would occur, 
from the approach of the higher layers of sandstone, (No. 4,) 
and the hard limestone, (No. 6,) to the surface of the water. 
There are various proofs of this halting, both in the form of 
the chasm below the present fall, and from the fact that this 
lower limestone still remains in place ; for it is seen that 
having passed a few feet beneath the water at the cascade, 
it supports large fragments of the upper limestone fallen from 
above. 

The conclusion then, seems inevitable, that the river has 
been the great agent in excavating its own channel, from near 
the escarpment between Lewiston and Queenston, to the 
present position of the cataract ; that the recession has been 
aided by the character of the rocks, presenting alternate hard 
and soft strata ;— and that the descent was overcome, not by 
one perpendicular fall, but by several, produced by the suc- 
cessive harder layers. In support of this latter assertion, a 
single analogous case will furnish stronger evidence than a 
long argument. 

3 



18 HalVs Remarks on Niagara Falls 

The course of the Oak Orchard creek, in Orleans County, 
is over the same strata, and furnishes direct confirmation of 
the succession of falls and rapids, precisely in the manner I 
have just enumerated. But as this is little known, I will ad- 
duce that of the Genesee river, in its descent from Rochester 
to Lake Ontario. 

In consequence of the dip of the strata, or from its absence, 
the hard, quartzose sandstone (No. 2,) of the Niagara section 
does not appear in the Genesee river. On entering the river 
from the lake, we find an open channel for five miles, where 
the river descends perpendicularly for about one hundred feet 
from the top of the sandstone, No. 4. The hard limestone 
layer, or one filling the place of that at Niagara, has retreated 
a quarter of a mile farther up the river, where it forms a fall 
of twentyfive feet. This recession of the limestone, beyond 
the sandstone, is owing to a mass of green shale below it, 
twentythree feet thick, while at Niagara the same shale is but 
four feet thick. From this place to the upper fall, about a 
mile and a half distant, we have a rapid stream. This fall is 
one hundred and ten feet high, and over precisely the same 
rocks as the Niagara fall at present, viz. Nos. 7 and 8 of sec- 
tion, the Niagara shale and limestone. The limestone at the 
top of the fall is much thinner than that at Niagara, in conse- 
quence of the less recession into the mass, as well as from 
being thinner as a whole. We have here a case precisely 
analogous to Niagara as I have supposed it to have been for- 
merly. 

Had there been a quantity of water flowing down the 
Genesee equal to the Niagara, the upper fall would have been 
excavated farther backward, and the lower fall, in all proba- 
bility entirely obliterated, presenting a rapid current from the 
upper fall to the present site of the Rochester landing. There 
appears here positive proof that there never has been so large 
a body of water passing down the Genesee as down the Ni- 
agara, and the concurring testimony is to the eff'ect that the 
wearing action has been far less. The recession of the lower 
falls at Rochester would add little or nothing to the height of 
the upper ; for the ascent of the river bed, and the dip of the 



and the Geology of the Surrounding Country. 19 

strata, would cause the disappearance of the whole beneath 
the water, before reaching that point. 

In support of the hypothesis that streams do cut back their 
channels, we may adduce sufficient evidence. An observation 
of the last four or five years upon the waterfalls of Western 
New York, has furnished positive evidence of their recession. 
Among these may be noticed the falls on Jacock's run, near 
? Genese$, and Fall brook, a few miles further south, both of 
which have evidently receded, from the undermining of the 
platform over which the water is precipitated. The amount 
during this time is very small, but sufficient to be appreciated. 
The lower falls of Portage furnish another example of reces- 
sion, where large masses have been removed, the channel 
deepened, and cut backwards many feet in the space of four 
years. 

Lateral streams flowing into ravines or river courses, furnish 
the most palpable evidence of the excavating power of water. 
The channel of Wolf creek, which comes into the Genesee 
through a perpendicular wall of rock, is a good example of 
this kind, where the evidence is conclusive that the excava- 
ting power is alone due to the stream. The junction of a 
small stream with the Genesee, on the west side, below Roch- 
ester, furnishes another example of this power. This stream 
has cut its channel through soft shale for fifty feet or more, a 
bed of hmestone eighteen feet thick, a bed of shale of equal 
thickness, and below this another bed of limestone nearly 
equal to the upper one. Many more examples of a similar 
kind might be named, on the Seneca and Cayuga lakes, and 
their valleys continued to the south. 

A remarkable fact connected with these lateral water courses 
is that their dimensions bear some proportion to their present 
quantity of water. And although the actual quantity flowing 
in any stream may seem insufficient to excavate its bed, yet I 
believe, generally, the largest streams will be found in the 
largest ravines, and the small lateral streams have always a 
proportionately smaller channel. If in any case we find the 
stream debouching into the lake, river, or valley, through a 
chasm with nearly perpendicular sides, and little or no wider 



20 HalVs Remarks ofi Niagara Falls 

than it is farther up the stream, we may infer that the action 
of the sea has had nothing to do with its excavation. 

So far as our present knowledge extends, regarding the 
mode of excavation by streams, conjointly with the action of 
the sea upon cliffs, I consider the question regarding Niagara 
as settled ; both by the analogy thus afforded, and by the ex- 
amples of streams passing over the same succession of rocks ; 
as the Oak Orchard creek and the Genesee river. The nar- 
rowness of the chasm from Lewiston to the site of the present 
cascade, the nearly perpendicular sides, and the absence of 
drift within its banks, are strong negative facts in support of 
the proposition. The evidence that the falls are now reced- 
ing, and the incontestible proof that they have receded con- 
siderably since this region has been inhabited, are positive 
facts in favor of the hypothesis. Within four years, a large 
triangular mass has disappeared from the top of the American 
fall, and the outline is becoming more curved. At several 
successive periods, large masses have fallen from the table 
rock, on the Canada side, which has considerably changed the 
outline of the fall. 

There is still further evidence that the waters of the Ni- 
agara river have once extended much nearer to the brow of 
the escarpment than they do at present. The nature of this 
evidence I pointed out in my report on the fourth Geological 
District of New York, in 1838, pages 271, 272, and 273. At 
that time, I was not aware that the same phenomena had 
before been noticed, though I have since learned that the ex- 
istence of fresh water deposits in Goat Island had been men- 
tioned some years previous. Whether the important inference 
had been deduced from this fact or not, I do not know. 

Goat Island stands upon the top of the precipice separating 
the two falls ; it is formed by the accumulation of gravel, 
sand, and clay, upon the surface of the limestone, and is evi- 
dently a portion of a once much more extensive deposit. 
Upon the southern side of this island, where there is an es- 
carpment, the thickness of the mass is about twentyfive feet. 
The upper half of the deposit consists of coarse gravel and 
sand, with abundance of fresh water shells of the genera 



and the Geology of the Surrounding Country. 21 

Unio, Cyclas, Limnea, Planorbis, Valvata, and Melania ; the 
same both in genera and species as those now inhabiting the 
river and lakes. The occurrence of these shells, in this situ- 
ation, about twentyfive feet higher than the top of the fall, 
proves the existence of a river or lake at an elevation suffi- 
cient to allow of such a deposition, for this accumulation of 
shells and gravel bears all the evidence of a fiuviatile deposit. 
During the past season, in company with my friend, Mr. 
Lyell, I re-examined this region, and upon the east side of the 
river, in a terrace about the same elevation as Goat Island, we 
discovered the Cyclas, Valvata, &/C. which had been thrown 
from an excavation made several years since. At the same 
place, a tooth and some bones of the Mastodon were discover- 
ed eleven feet beneath the fiuviatile deposit. Farther north- 
ward, and more than half a mile north of Goat Island, in 
another excavation, we discovered similar shells. We also 
noticed the continuation of this terrace, or one about the same 
elevation, as far north as the whirlpool. We did not search 
for shells in it at this place ; but from its character and posi- 
tion there can be little doubt but it is a continuation of the 
same deposit, and probably will be found to contain the same 
shells. Now in order to raise the water of the river to suffi- 
cient height to make this deposit, it would require a barrier 
for the water at some distance north of the whirlpool. On 
the other side of the river a similar terrace exists, but this I 
have not particularly examined.* Now these banks or terra- 
ces on either side of the river, and that of Goat Island, are 
clearly not deposits made in this form, but the remains of a 
once much more extensive one. During the time of its de- 
position the river occupied this valley, having its barrier far 
towards Lewiston. In the bed of this expanded river or lake, 
much as it now is above the rapids, this deposit was made, 
covering the whole extent ; but from the wearing back of the 
fall it has been carried off, the margin only being left on 
either side, and a small portion of the central part forming 
Goat Island. The following diagram will exhibit the posi- 

• Mr. Hayes speaks of th:^ terraces on both sides of the river, as containing 
fresh water deposits. Amer. Journnl of Science, Vol. XXXV, No. I. 



22 



HalVs Remarks on Niagara Falls 



tion of this fresh water deposit. It is a cross section of the 
river at the falls. 




a. The terrace with shells on the eastern side. 

h. Goat Island, c. The terrace on the Canada side. 

d. The ancient drift. L. Limestone. S. Shale. 

From its present position, it seems to have been a continu- 
ous deposit, the greater part of which has been removed. 
The mode of its formation can be well illustrated by referring 
to Fig. 1, which is intended to represent what is now going 
on above the rapids, in the broad expansion of the river. 
a. a. represents the fluviatile deposit made by materials 
brought down by the current, and doubtless mingled with a 
large accumulation of shells of Unio, Melania, Anculotus, &c. 
as these shells are abundant above the falls, and large num- 
bers of the shells of Uniones are constantly brought down the 
rapids during the summer season. 

The single terrace containing shells is not the only one, for 
on the eastern side, at lower elevations, there are in succession 
two others, which seem to be remains of the deposit in the 
river bed, as it successively excavated its barrier to the north, 
and receded towards its present position. For the greater 
Dart of the distance from the falls to Black Rock, on the east- 
ern side there is a terrace or bank a few feet higher than the 
river, which may have originally limited its waters when it 
stood at the level indicated by the fresh water deposit of Goat 
Island. Near Black Rock, and bordering the valley of the 
Tonawanda, there is a terrace some twenty feet higher, 
which appears to have been the boundary of the river or lake 
at a still earlier period ; but with these we have, at present, 
nothing to do. The existence of the fluviatile deposit of 
Goat Island, and at the same level on the eastern side of the 



and the Geology of the Surrounding Country, 23 

river, requires for its elucidation the existence of water stand- 
ing at a level somewhat higher, in order to allow of the de- 
posit being made in the bed of the stream. To accomplish 
this, a barrier is required further north than the whirlpool, 
and about the height of the surface of limestone between this 
and Lewiston. The occurrence of successive terraces below 
this one, proves that the drainage to the present point was not 
effected suddenly. 

There is another fact which should be noticed, as proving 
the existence of a current from south to north, during the de- 
position of the materials forming Goat Island. The pebbles, 
at least large numbers of them, are of the limestone of Black 
Rock, and the harder layers of the saliferous formation, like 
the rock in place at the upper end of Grand Island. The 
surface of the rock, on which the deposit forming Goat Island 
is made, is smoothed and scratched, as are the surrounding 
surfaces both in the rapids and on either bank of the river. 
The deposit is of greatest thickness towards the fall, and thins 
entirely out at its eastern extremity. 

There is another indentation on the eastern bank of the 
Niagara, below the whirlpool. This has been cited as a case 
where the small stream coming in, is insufficient to account 
for such an excavation. *= It occurs at the junction of Bloody 
run and the river, and bears the strongest evidence of having 
been produced by the common agents, frost and water. The 
wearing action of the stream alone is probably insufficient to 
produce this short ravine, which extends a few rods back from 
the margin of the river bank ; but when we take into con- 
sideration the fact that the water penetrates all the fissures of 
the rock, and then, during fall and winter, expands by freez- 
ing, we shall find means of explaining the mode of operation. 
At the falls, the recession is by the undermining and breaking 
down of the upper masses ; the action of frost is not to be 
taken into consideration, as the water never freezes. Now I 
consider it as an established fact, that small streams, which 
freeze during winter, will excavate their beds more rapidly 

• Am. Journal of Science, Vol. XXXV, No. I. 



24 HalVs Remarks on Niagara Falls 

in proportion, than large bodies of water, which never freeze. 
It appears to me that the indentation at Bloody run is not 
greater than might be expected to have taken place while 
the main channel receded to its present position. 

Whatever facts and arguments may be advanced to prove 
the existence of phenomena indicating the former action of 
the sea in excavating the Niagara channel, and whatever ob- 
jections may be advanced for or against other theories, I am 
fully of opinion that the existence of the falls and the Niagara 
river, in their present position, is of very recent date, geologi- 
cally speaking. I cannot resist the belief that at some previ- 
ous period the waters of the upper lakes were discharged into 
Ontario at its western extremity, and that subsequently, from 
causes which at present I have not facts sufficient to explain, 
the course was changed, and the outlet made through Lake 
Erie. Previous to this time, there may have been a small 
stream flowing in the direction of the present Niagara. 

We come now to consider the future recession of Niagara 
falls, and its consequences. This is a subject on which many 
speculations have been hazarded, but no one appears to have 
undertaken the calculation with a full knowledge of the geol- 
ogy of the district, or to have taken into account the many 
disturbing influences. At the present time, the cliff" over 
which the water is precipitated, is nearly equally divided be- 
tween thick bedded limestone and soft, disintegrating shale. 
It is by the action of the spray from the falling water upon 
the shale, undermining and leaving the limestone unsupported, 
which falls down by its own weight, that the falls recede from 
their present position. Now if we believe the statements of 
those who have resided at the falls, the recession has been 
about fifty yards within the last forty years ; but from all the 
data I have been able to obtain, it appears to be much too 
great an estimate ; indeed, it is extremely questionable if the 
fall has receded as many feet within that time. The central 
portion of the Canada fall recedes more rapidly than any other 
part, for here the greatest force of the river is exerted. We 
know, likewise, from the testimony of all residents at this 
place, that the American fall is becoming more curved in its 



and the Geology of the Surrounding Country. 25 

outline, whereas formerly it was nearly in a straight line. 
The successive descent of large masses of limestone, and the 
still continued overhanging of the table rock, prove very con- 
clusively the unremitting action of water and air upon the 
shale below. 

In ihe absence of established landmarks, we are compelled 
to leave the rate of recession unsettled for the present : and 
the only mode by which this can be determined accurately is, 
by a systematic survey and triangulation of the form of the 
cascade, and ihe establishment of permanent marks of refer- 
ence for future observers. 

Leaving out of view the time or rate of recession, we have 
sufficient data to establish with certainty the future changes 
which will supervene, allowing the recession to go on as it is 
now doing. The lower half of the rock at the cascade, or 
about eighty feet, is of soft shale, the limestone above being 
of equal thickness ; higher still is about forty feet of thin, 
bedded limestone, forming the rapids. These different rocks 
are represented in the section as 7, 8 and 8', respectively. 
Now these beds dip to the south at the rate of about twenty- 
five feet in the mile, and (he declivity of the bed of the river 
is about fifteen feet in the mile, from the falls to Lewiston. 
It follows, therefore, that as the falls recede, there will be a 
less amount of shale above water, owing to the dip, and to 
this must be added the amount of declivity in the river bed, 
both together making forty feet. So that when the fall has 
receded one mile, the surface of the water will stand at A:., 
or a point in the shale half way between the present surface 
of the water and the bottom of the limestone. Going on at 
this rate for another mile would take away from the fall forty 
feet more of the shale, so that the surface of the river would 
stand at p. or the base of the limestone. 

The cataract would then have a solid wall of limestone to 
wear down, the river beneath protecting, in a great measure, 
the undermining action upon the shale. During this time, 
and at the end of the first mile, the falls would have arrived 
at the present site of the commencement of the rapids, and 
thus about forty feet more of limestone would be added to 
4 



26 Hall's Remarks on Niagara Palls 

the height ; unless from its thin bedded character it continued 
to recede faster, and thus continue a rapid. In this case, 
there would be a fall of one hundred and twenty feet at the 
end of the first mile {i, k.) ; and one of eighty feet (o. p.) at 
the end of the second mile. 

At this period, then, we are to contemplate the cataract of 
Niagara as having receded two miles, the shale having disap- 
peared beneath the river, and the cascade presenting a solid 
wall of limestone eighty feet high, and a rapid of forty or fifty 
feet (o. ')n.) beyond. The recession would then go on very 
gradually, and so soon as masses from this cliff* have fallen 
down to fill up the river bed, as they inevitably will in a 
great measure, then the base will be protected so effectually 
that little influence will be exerted by the force of the water. 
Eventually, however, the cliff will be broken down, and huge 
fragments piled up below, until the cataract will be nearly 
lost amid them. This state of things will continue for a long 
time, the height gradually diminishing, till the river has cut 
its way back for two miles further, when there will be no 
thick bedded limestone above water, and the higher beds will 
form a rapid a^ before. 

This point of meeting, between the surface of the river 
and the top of the thick bedded limestone, will be about one 
hundred feet lower than the summit of the present cascade, 
and as there will be forty feet of rapids in the thin bedded 
limestone within a short space, as there now is, it follows that 
there will be added to the descent of the river beyond the 
rapids, one hundred feet more than at present, as the surface 
of the limestone has dipped to that amount. The whole fall 
in the river at that time, from Lake Erie to the point of junc- 
tion between the limestone and water below the rapids {h. o.), 
will be about one hundred and sixty feet. The distance 
between this point and Lake Erie is occupied by nearly uni- 
form soft layers, and after a partial wearing down of the lime- 
stone forming the rapids, the descent will be equally distributed 
over the whole extent of sixteen miles, giving a uniform de- 
clivity of about ten feet in the mile, or one third less than 
the present declivity in the bed of the river from the falls to 



and the Geology of the Surrounding Country. 27 

Lewiston. From the nature of the bed of the river for fifteen 
miles below Lake Erie, it may be doubted whether this rapid 
descent along the whole distance would be continued; for 
the stream, having no heavy blocks of rock to remove, would 
keep its channel clear with a far less declivity ; and should 
this prove the case here, we might still have a fall of a few 
feet, at the outlet of Lake Erie, over the limestone succeeding 
the saliferous group. 

Whether such a fall would occur at the outlet of Lake Erie, 
depends on the solution of the problem regarding the acquired >•< 
declivity in the bed of the river below Lake Erie, Which- 
ever way it may occur it will make no material difference in 
the great result, which will be either a continuous rapid 
stream from Lake Erie to Lewiston, or a rapid stream with a 
fall at the outlet of Erie. If present causes continue to ope- 
rate as now, such will be the consummation, the finale, of 
the grand cataract of Niagara. 

It is unnecessary here to follow on this recession gradually 
from the outlet of Lake Erie to the final drainage of a great 
portion of its waters. The views which have been enter- 
tained of the sudden drainage of this or any of the upper 
lakes, and a deluging of the country on the north and east 
are no longer considered as tenable by any one, and even 
if Lake Erie could be drained suddenly, it would cause no 
deluge of any importance. If the whole lake were at once 
placed upon Lake Ontario, it would only elevate its surface 
by about one hundred and fifty feet, so that its extent would 
scarcely exceed the limits of the ancient lake ridge, and the 
outlet would still be the valley of the St. Lawrence. 

In calculating the future recession of Niagara falls, there 
are many disturbing influences to be considered. At the 
present time, by means of the Erie and Welland canals, large 
quantities of water, which formerly flowed over the fall, are 
returned to Lake Ontario by other than the natural channels. 
The Illinois canal, at the southern extremity of Lake Michigan, 
will drain a large amount of water in that direction, which 
will find its way to the ocean through the Mississippi river 
and Gulf of Mexico, Extensive improvements have been 



28 HalVs Remarks on Niagara Falls 

contemplated at the falls, and the erection of manufactories, 
by which great quantities of water from above the rapids will 
be returned to the Niagara channel below the falls. Thus far 
the country supplying water to the upper lakes has been but 
little changed by the hand of cultivation, the piimeval forests 
still cloihe the surface, and evaporation to a gieot extent is 
prevented. This cannot always remain so ; the advancing 
settlements will yet penetrate even the wilderness bordering 
Lake Superior, and the opening of the sarfuce to the influence 
of the sun's rays will greatly diminish Uie supply of water 
flowing into the tributaries. These causes will sensibly di- 
minish the quantity passing down the natural outlet ; and the 
mighty Niagara, the " Thunder of Waters,'''' is destined to be 
at certain seasons but a diminutive representative of its former 
grandeur. 

Note. Since writing the foregoing paper, I have referred to 
some notes and correspondence with Mr. FiO]^, Government 
Engineer at Toronto, U. C. From levels which he has made 
from Lake Ontario to the (iueenslon heights, at several places, 
he says the crest of the terrace constantly declines going 
westward from the river, while the base continues at the same 
elevation. This fact is opposed to information I had before 
received, and to the general belief. If this be substantiated, 
and I have every reason to believe the statement, it may ma- 
terially alter the reasoning in regard to ihe former recession, 
of the falls, and the manner in which the chasm has been 
excavated. 

From the Niagara river there is a declinption of the crest of 
the terrace eastward, so that at Rochester its summit is about 
sixtyfive feet below the level of Lake Erie ; giving in this 
direction a descent of about one hundred feet in eight v miles.* 
I have no data for determining the rate of declination wester- 
ly, but whatever it may be, it proves the coarse of the Niagara 
to be upon or near the highest part of this terrace. If this 
inequality of the surface was produced by some force after 

' See New York Geological IlHports. 



and the Geology of the Surrounding Country. 29 

the strata became consolidated, there might have been pro- 
duced a rent in this direction, as in the diagram which repre- 
sents a transverse section. 

This may iiave been the first cause of directing the water 
in its present channel, which was afterwards widened by the 
river. There seems some reason to suppose this may have 
been the case, from the general direction of the chasm, being 
at right angles wifh the stiike of the strata. If this be true, 
however, the fissure must have been extremely narrow, and 
still have left lo the river the work of excavation, though 
under very different circumstances. The reasoning in regard 
to the existence of p depression previous to the excavation of 
a deep channel, will still hold true, as well as that regarding 
the fresh water deposits, and (he terrace extending to the 
whirlpool. The future recession of the cataract cannot be 
affected in auy manner by this fact, for if such a rent ever 
existed, it seems i)ot to have extended as far as the present 
site of the falls, for all ilie testimony is to the effect that the 
process of retrogression goes on by the action of the water 
upon the shale, which undermines the limestone. If there 
was a fissure in the course of the Niagara, it did not reach so 
deep as the bed of the river, for it seems quite certain that 
the thick bed of sandstone (No. 2, of section,) has never been 
excavated very deeply below the present surface of the river. 
If these views regarding the elevation of the terrace are 
found to hold true, it will aid in establishing the opinion be- 
fore expressed, that the present channel of Niagara is of 
recent date. I have long believed that the former outlet of 
the great Lakes was by the western end of Lake Ontario, 
though I have not been able to make investigations to the 
extent desired in order to establish that opinion. 

The period when the disturbance of the strata took place, 
is one of great importance, and may aid in determining the 
comparative age of the Niagara channel, and the period of the 
drift. That the former was subsequent, however, does not 
admit of doubt. I am not aware how far the terrace contin- 
ues to decline westward from the Niagara river, but it is quite 
certain that the limestone rises before going as far west as the 



30 Perkins^ Remarks on Fossil Bones 

head of Lake Erie ; for we find crossing this lake near its 
western extremity, an anticlinal axis which extends northward 
into Canada, and southward entirely across the State of Ohio. 
Now this may have happened at the same period as the disturb- 
ance or uplift, further east, and the production of this western 
axis may have resulted in turning the course of the outlet, and 
the formation of the Niagara river ; but more facts are required 
before any speculations can be offered upon this subject. 



LIBRARY OF CONGRESS 



e 014 221 264 ft 



